Refining hydrocarbons



Fatented Get. 29, 1935 Thomas T. Gray, Elizabeth, N. 3., assignor toThe Gray Processes Corporation, Newark. N. 3.. a corporation oi Delaware No Bra Application liecember 3, 1929,

Serial Ne. erases 5 (Jlaims. (Cl. lea-=96) This invention relates to the refining of petroleum hydrocarbons and more particularly to the treatment of such hydrocarbons to eliect the removal therefrom of sulphur compounds. Many crude petroleums contain sulphur and it's compounds which are distributed more or less through the entire boiling range of the petroleums and are present in all the products obtained therefrom. These sulphur compounds have a deleterious effect on the products in which they exist as impurities. This is especially true in the case of gasoline which is used as a motor fuel and'in the case of burning oil for use in lamps such as kerosene. -The U. S. Bureau of Mines has seen fit to establish a limit of one-tenth per cent as a maximum allowable content of sulphur in gasoline. It has heretofore been almost impossiole to attain this limit in the case of many straight run and cracked gasolines except by resorting to chemical treatment, not only costly in itself, but resulting in large losses of the products being refined.

An object of this invention is an improved desulphurizing process which is inexpensive to practice and with which there is substantially no loss of the products being refined. I have found that by vaporizing hydrocarbon fractions containing sulphur and passing the vapors into con-v tact with fullers earth at a high temperature, the sulphur compounds are decomposed and either retained by the earth or are transformed into other compounds which can be very readily removed and with comparatively little loss.

In carrying out this process for desulphurizing gasoline or other petroleum fractions, I have found that the best temperatures of operation are in the range between 550 F. and 850 F. Desulphurization is also effected at. temperatures below and above this range, but below 550 F. the desulphurization is less substantial in amount and above 850 F. the fractions are subjected to cracking conditions and undesirable changes in the hydrocarbons are effected along with the decomposition of the sulphur compounds. Within the indicated range, I find the greatest conversion-of sulphur compounds compatible with the absence of cracking or conversion of hydrocarbons. The fullers earth may be heated to the proper temperature by pre-heating the vapors to be refined to such a temperature that they heat the fullers earth to the required extent on contacting therewith or the fullers earth may be heated by. any other suitable means. Apparatus for carrying out the process in either of the ways above indicated will readily suggest itself to those skilled in the art.

rhe sulphur compounds contained in the gasoline vapors upon being contacted with fullers earth at the temperatures indicated are decom- 5 posed from the refractory difficultly removable form in which they ordinarily exist to other sulphur compounds. Some of the latter are retained by the fullers earth while others remain in the fraction and can be removed by a subsequent treatment, such as or similar to that hereinafter described. I

After contact with the fullers earth, the fraction is condensed and preferably is washed with a solution of caustic soda or similar treating solution. I have found that the washing operation efiectively removes the converted sulphur compounds and leaves a product, such for example as gasoline having a substantially lower sulphur content than before treatment as above described. This shows that the refractory sulphur compounds originally present and which can only be removed with accompanying large losses of hydrocarbons have been converted into other sulphur compounds whereby substantial'amounts of the sulphur originally present in refractory form is now present as hydrogen sulphide and light mercaptans.

The process above described enables me to effect sulphur reduction with very much smaller losses and very much more economically than by using chemical treating agents. The activity of the fuller's earth will decrease in time and it will eventually be necessary to replace the spent fullers earth with fresh fullers earth. However, spent fullers earth can be revivifled by roasting in the manner well-knownin the art and after its reviviflcatlon can be again used. As

.a result, the material cost is very low.

In some cases, I have found it advantageous to 40 pass the vapors through several beds of fullers earth or through the same bed several times, as additional desulphurization may be effected in this manner. In other cases, however, it issumcient to pass the treated vapors through the bed a single time to effect the required desulphurization and in such cases, the re-passing of the treated vapors has no beneficial efiect.

The treatment may 'be carried out at atmospheric or super-atmospheric pressure, so long as 50,

the temperature is maintained within the range above specified. In the treating of some distillates, I have found it to be advantageous to add steam-to the same. p

I am aware that desulphurizing processes have been suggested using bauxite, copper oxide and other substances having a chemical reaction on the sulphur compounds or the vapors, but my process distinguishes from these by being merely a high temperature decomposition efl'ected by the comparatively inert material. fuller's earth.

t treated gasoline therefrom.

2. The process 01 refining gasoline containing sulphur compounds into easily removable sulphur compounds by subjecting said gasoline in vapor 10m to contact with i'uller's earth at a tam perature of from 550 to 850 1".. condensing the vapors, and washing the condensate with a soluticn capable of removing said easily removable sulphur compounds.

8.'.l'heprocessotrcilninggasolinecontaining as impurities sulphurcompoimds diiflcult to remove in the ordinary manner, which comm-lacs converting the said diilicultly removable sulphur compounds into easily removable sulphur compounds by subjecting said gasoline in vapor form 5 to contact with fullers earth at a temperature of from 550 to 850 F., condensing the vapors and washing the condensate with an alkaline soda solution. I

4. The process 01 refining gasoline containing to as impurities sulphur compounds diiiicult to remove in the ordinary manner. which comprises converting the said dimcultly removable sulphur compounds into easily removable sulphur comr pounds by subjecting said gasoline in vapor iorm to contact with iullers earth at a temperature of from 550 to 850 F., removing the vapors from contact with said iullers earth, condensing the vapors without permitting the vapors to come into contact with iullers earth at a temperature "substantially below thespecified temperature nge, and washing the condensate to remove said easily removable sulphmcompounds.

5. The process of refining gasoline containing as impurities sulphur compounds diflicult to remove in the ordinary manner, which comprises converting the said diiiicultly removable sulphur compounds into easily removable sulphur compounds by subjecting said gasoline in vapor form to contact with fullers earth at a temperature of from 650' to.'750 F., rem the vapors containing said easily removable sulphur compounds and condensing them to recover the treated gasoline therefrom.

mouse '1'. GRAY. 

